Make TabViewer::id mandatory (#324)

* Make TabViewer::id mandatory

* Fix example formatting

* Fix missing id and Debug implementations

---------

Co-authored-by: Adam Gąsior <adanos020@gmail.com>

Author: dolezvo1

examples/hello.rs

@@ -90,6 +90,10 @@ struct MyApp {
 impl TabViewer for MyContext {
     type Tab = String;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, tab: &mut Self::Tab) -> WidgetText {
         tab.as_str().into()
     }

examples/reject_windows.rs

@@ -14,30 +14,37 @@ fn main() -> eframe::Result<()> {
 
 struct TabViewer;
 
+#[derive(Hash, Debug)]
+enum Opinion {
+    Changing(bool),
+    Fixed(bool),
+}
+#[derive(Hash, Debug)]
 struct OpinionatedTab {
-    can_become_window: Result<bool, bool>,
+    can_become_window: Opinion,
     title: String,
     content: String,
 }
 
 impl egui_dock::TabViewer for TabViewer {
     type Tab = OpinionatedTab;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, tab: &mut Self::Tab) -> egui::WidgetText {
         (&tab.title).into()
     }
 
     fn ui(&mut self, ui: &mut egui::Ui, tab: &mut Self::Tab) {
         ui.label(&tab.content);
         match &mut tab.can_become_window {
-            Ok(changing_opinion) => {
-                ui.add(egui::Checkbox::new(
-                    changing_opinion,
-                    "can be turned into window",
-                ));
+            Opinion::Changing(opinion) => {
+                ui.add(egui::Checkbox::new(opinion, "can be turned into window"));
             }
-            Err(fixed_opinion) => {
-                if *fixed_opinion {
+            Opinion::Fixed(opinion) => {
+                if *opinion {
                     ui.small("this tab can exist in a window");
                 } else {
                     ui.small("this tab cannot exist in a window");
@@ -48,7 +55,7 @@ impl egui_dock::TabViewer for TabViewer {
 
     fn allowed_in_windows(&self, tab: &mut Self::Tab) -> bool {
         match tab.can_become_window {
-            Ok(opinion) | Err(opinion) => opinion,
+            Opinion::Changing(opinion) | Opinion::Fixed(opinion) => opinion,
         }
     }
 }
@@ -61,12 +68,12 @@ impl Default for MyApp {
     fn default() -> Self {
         let mut tree = DockState::new(vec![
             OpinionatedTab {
-                can_become_window: Ok(false),
+                can_become_window: Opinion::Changing(false),
                 title: "old tab".to_owned(),
                 content: "since when could tabs become windows?".to_string(),
             },
             OpinionatedTab {
-                can_become_window: Err(false),
+                can_become_window: Opinion::Fixed(false),
                 title: "grumpy tab".to_owned(),
                 content: "I don't want to be a window!".to_string(),
             },
@@ -77,7 +84,7 @@ impl Default for MyApp {
             NodeIndex::root(),
             0.6,
             vec![OpinionatedTab {
-                can_become_window: Ok(true),
+                can_become_window: Opinion::Changing(true),
                 title: "wise tab".to_owned(),
                 content: "egui_dock 0.7!".to_string(),
             }],
@@ -86,7 +93,7 @@ impl Default for MyApp {
             a,
             0.4,
             vec![OpinionatedTab {
-                can_become_window: Ok(true),
+                can_become_window: Opinion::Changing(true),
                 title: "instructional tab".to_owned(),
                 content: "This demo is meant to showcase the ability for tabs to become/be placed inside windows. 
                 \nindividual tabs have the ability to accept/reject being put/turned into a window. 
@@ -96,7 +103,7 @@ impl Default for MyApp {
             }],
         );
         let _ = tree.add_window(vec![OpinionatedTab {
-            can_become_window: Err(true),
+            can_become_window: Opinion::Fixed(true),
             title: "egotistical tab".to_owned(),
             content: "im above you all!".to_string(),
         }]);

examples/save_load_dock_state.rs

@@ -23,6 +23,10 @@ struct TabViewer {
 impl egui_dock::TabViewer for TabViewer {
     type Tab = String;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, tab: &mut Self::Tab) -> egui::WidgetText {
         (&*tab).into()
     }

examples/simple.rs

@@ -18,6 +18,10 @@ struct TabViewer {}
 impl egui_dock::TabViewer for TabViewer {
     type Tab = String;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, tab: &mut Self::Tab) -> egui::WidgetText {
         (&*tab).into()
     }

examples/tab_add.rs

@@ -19,6 +19,10 @@ struct TabViewer<'a> {
 impl egui_dock::TabViewer for TabViewer<'_> {
     type Tab = usize;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, tab: &mut Self::Tab) -> egui::WidgetText {
         format!("Tab {tab}").into()
     }

examples/tab_add_popup.rs

@@ -13,11 +13,13 @@ fn main() -> eframe::Result<()> {
     )
 }
 
+#[derive(Hash, Debug)]
 enum MyTabKind {
     Regular,
     Fancy,
 }
 
+#[derive(Hash, Debug)]
 struct MyTab {
     kind: MyTabKind,
     path: NodePath,
@@ -68,6 +70,10 @@ struct TabViewer<'a> {
 impl egui_dock::TabViewer for TabViewer<'_> {
     type Tab = MyTab;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, tab: &mut Self::Tab) -> egui::WidgetText {
         tab.title().into()
     }

examples/text_editor.rs

@@ -24,6 +24,10 @@ struct Buffers {
 impl TabViewer for Buffers {
     type Tab = Title;
 
+    fn id(&mut self, tab: &mut Self::Tab) -> egui::Id {
+        egui::Id::new(tab)
+    }
+
     fn title(&mut self, title: &mut Title) -> egui::WidgetText {
         egui::WidgetText::from(&*title)
     }

src/lib.rs

@@ -15,7 +15,7 @@
 //!
 //! ```rust
 //! use egui_dock::{DockArea, DockState, NodeIndex, Style, TabViewer};
-//! use egui::{Ui, WidgetText};
+//! use egui::{Id, Ui, WidgetText};
 //!
 //! // First, let's pick a type that we'll use to attach some data to each tab.
 //! // It can be any type.
@@ -30,6 +30,11 @@
 //!     // This associated type is used to attach some data to each tab.
 //!     type Tab = Tab;
 //!
+//!     // Returns the unique ID for the `tab`.
+//!     fn id(&mut self, tab: &mut Self::Tab) -> Id {
+//!         Id::new(tab)
+//!     }
+//!
 //!     // Returns the current `tab`'s title.
 //!     fn title(&mut self, tab: &mut Self::Tab) -> WidgetText {
 //!         tab.as_str().into()
@@ -86,10 +91,11 @@
 //!
 //! ```rust
 //! # use egui_dock::{DockArea, DockState, OverlayType, Style, TabAddAlign, TabViewer};
-//! # use egui::{Ui, WidgetText};
+//! # use egui::{Id, Ui, WidgetText};
 //! # struct MyTabViewer;
 //! # impl TabViewer for MyTabViewer {
 //! #     type Tab = ();
+//! #     fn id(&mut self, tab: &mut Self::Tab) -> Id { Id::new(tab) }
 //! #     fn title(&mut self, tab: &mut Self::Tab) -> WidgetText { WidgetText::default() }
 //! #     fn ui(&mut self, ui: &mut Ui, tab: &mut Self::Tab) {}
 //! # }

src/style.rs

@@ -20,10 +20,11 @@ pub enum TabAddAlign {
 ///
 /// ```rust
 /// # use egui_dock::{DockArea, DockState, OverlayType, Style, TabAddAlign, TabViewer};
-/// # use egui::{Ui, WidgetText};
+/// # use egui::{Id, Ui, WidgetText};
 /// # struct MyTabViewer;
 /// # impl TabViewer for MyTabViewer {
 /// #     type Tab = ();
+/// #     fn id(&mut self, tab: &mut Self::Tab) -> Id { Id::new(tab) }
 /// #     fn title(&mut self, tab: &mut Self::Tab) -> WidgetText { WidgetText::default() }
 /// #     fn ui(&mut self, ui: &mut Ui, tab: &mut Self::Tab) {}
 /// # }

src/widgets/tab_viewer.rs

@@ -7,6 +7,13 @@ pub trait TabViewer {
     /// The type of tab in which you can store state to be drawn in your tabs.
     type Tab;
 
+    /// Unique ID for this tab.
+    ///
+    /// Assuming `Tab` implements `Hash`, you can simply do `Id::new(tab)`.
+    /// If that is not possible, but tab names are guaranteed to be unique,
+    /// one could also implement this as `Id::new(self.title(tab).text())`.
+    fn id(&mut self, tab: &mut Self::Tab) -> Id;
+
     /// The title to be displayed in the tab bar.
     fn title(&mut self, tab: &mut Self::Tab) -> WidgetText;
 
@@ -19,13 +26,6 @@ pub trait TabViewer {
     /// that this particular context menu belongs to.
     fn context_menu(&mut self, _ui: &mut Ui, _tab: &mut Self::Tab, _path: NodePath) {}
 
-    /// Unique ID for this tab.
-    ///
-    /// If not implemented, uses tab title text as an ID source.
-    fn id(&mut self, tab: &mut Self::Tab) -> Id {
-        Id::new(self.title(tab).text())
-    }
-
     /// Called after each tab button is shown, so you can add a tooltip, check for clicks, etc.
     fn on_tab_button(&mut self, _tab: &mut Self::Tab, _response: &egui::Response) {}